The present invention relates to a chuck for a tool such as a drill.
The present applicant discloses a chuck in Japanese Patent Application No. 63-119597 (hereinafter referred to as the prior art chuck) as shown in FIG. 9. In the prior art chuck, a buffer stop cylinder 56, which is slidable relative to a rotational sleeve 53 that is not slidable in the axial direction nor rotatable relative to the buffer stop cylinder 56 by engagement of splines 57 with spline grooves 58, is fitted to the rotatable operational sleeve 53. When the buffer stop cylinder 56 is positioned by engaging a convex portion 59, formed on the outer peripheral portion thereof, with a concave portion 60 formed on the inner peripheral surface of a grip sleeve 55, a serration portion 61 formed on the outer rear end portion of the buffer stop cylinder 56 is engaged with a serration portion 62 formed on the inner rear end portion of the grip sleeve 55, whereby the buffer stop cylinder 56 is kept unrotatable relative to the grip sleeve 55, and hence the rotational sleeve 53 is kept unrotatable also relative to the grip sleeve 55, thereby preventing the rotational sleeve 53 from being rotated relative to the chuck body 52 and ensuring the fastening effect of a working tool 54 with jaws 51.
It has been however found through various experiments that the prior art chuck has disadvantages or inconvenience in use. Namely, since the buffer stop cylinder 56 is provided around over the outer peripheral surface of the rotational sleeve 53 which is gripped by a user's hand and on which his palm contacts, it would be inconvenient to carry out the rotational operation of the rotational sleeve 53, and also after the rotational sleeve 53 has been rotated to thereby fasten a working tool 54 with jaws 51, a user has to let go his grip off the rotational sleeve 53 and slide the buffer stop cylinder 56, thus two actions are required on his hand's movement, which reduces the work efficiency.
A primary object of the invention is to provide a chuck for a tool which can overcome the above-noted disadvantages.